The internet is not floating in the air or stored in a cloud. It lives in a sprawling, physical network of fiber optic cables, data centers, and networking hardware spread across every continent and beneath every ocean. The bulk of the world’s internet traffic travels as pulses of light through glass strands thinner than a human hair, running along ocean floors, under city streets, and into massive warehouse-sized buildings filled with servers.
Undersea Cables Connect the Continents
More than 500 active and planned submarine cable systems span the globe as of 2024, connecting continents, markets, and households. These cables sit on the ocean floor, sometimes thousands of meters deep, carrying the vast majority of intercontinental data. When you load a website hosted on another continent, your request almost certainly travels through one of these cables rather than bouncing off a satellite.
Each cable contains bundles of glass fibers, and each fiber transmits data as pulses of light generated by small lasers. A single fiber can carry data at speeds up to 100 gigabits per second, and modern cables bundle many fibers together to multiply that capacity. The cables land at specific coastal stations where they transition from the ocean floor to terrestrial networks. Major landing points include Marseille in the Mediterranean, Virginia Beach and Myrtle Beach on the U.S. East Coast, and Singapore in Southeast Asia.
New routes are constantly being built. Projects like 2Africa and Equiano are expanding capacity across Africa and the Middle East. Echo and Bifrost will be the first cables to directly connect Singapore to the United States. Over $6 billion worth of new cables connecting Asia and Oceania were planned for activation between 2022 and 2024 alone. South America’s submarine cable connectivity, outside of a cable linking it to Europe, remains heavily focused on connections to the United States.
Data Centers Store and Serve Your Content
Every website, video, email, and cloud file you access is stored on a physical server inside a data center. These are large, climate-controlled buildings filled with rows of server racks, cooling systems, and backup power generators. The biggest ones cover hundreds of thousands of square feet.
The single largest concentration of data centers in the world is in Loudoun County, Virginia, in an area known as “Data Center Alley.” It has roughly 200 data centers already built and another 117 in development, more than the next six U.S. markets combined. The reason this area became so dominant is its extensive underground fiber optic network, which gives it the lowest latency (fastest response time) for moving data of any location in the world. That speed advantage has compounded over decades, attracting more and more companies.
Major data center companies operate facilities across the globe. Equinix, one of the largest, has 58 major projects underway worldwide. Digital Realty operates around 30 facilities across 21 markets. American Tower runs 30 facilities in the U.S. alone, totaling about four million square feet. These companies don’t just store their own data. They rent space and connectivity to thousands of other businesses, so a single building might house servers for dozens of different companies whose services you use every day.
The Hardware Between You and the Server
Between your device and the data center storing the content you want, your data passes through a chain of physical equipment. Your computer or phone contains a network interface controller, the chip that lets it connect to a network, whether through a Wi-Fi antenna or an ethernet port. From there, your data hits a router or gateway that connects your local network to the wider internet.
At the neighborhood level, your data might travel through a modem (for cable or DSL connections) or an optical network terminal if you have fiber internet to your home. It then enters your internet service provider’s local network, which feeds into metropolitan and regional networks. These regional networks connect to the internet’s backbone: high-capacity fiber optic trunk lines operated by major network service providers.
The backbone itself is built from fiber optic cable infrastructure. At every junction where networks meet, physical routers direct your data packets toward their destination. These routers are specialized computers, often housed in the same data centers and cable landing stations described above. The entire system works because all these physical layers are interconnected, with each segment handing data off to the next.
Satellites Play a Smaller Role
Satellites handle a small fraction of global internet traffic, primarily serving areas where laying cable is impractical: rural regions, ships at sea, aircraft, and disaster zones. SpaceX’s Starlink constellation is the most visible example. Users connect through a small satellite dish and router kit that communicates with satellites in low Earth orbit. Those satellites relay the signal to ground stations, which connect to the terrestrial fiber network.
Satellite internet is physically located in three places: the dish on your property, the satellites orbiting roughly 550 kilometers above Earth, and the ground gateway stations that bridge the satellite network back to the cable-based internet. It’s a useful supplement, but undersea and underground fiber still carries the overwhelming majority of the world’s data.
There Is No Single Location
The internet is physically distributed by design. No single building, cable, or country contains it. Your data might be stored in a server in Virginia, travel through fiber under the Atlantic, pass through a landing station in Marseille, cross overland cables through Europe, and arrive at your screen in seconds. The “cloud” is really just someone else’s computer in a very large, very well-cooled building, connected to your device by glass, light, and a chain of routers stretching across the planet.
That distributed nature is also what makes the internet resilient. When one cable is damaged or a data center goes offline, traffic reroutes through alternative paths. The physical internet is redundant on purpose, with multiple cables crossing each ocean and data centers clustered in dozens of major markets worldwide. The system you’re using right now to read this page is, at its core, a global web of glass fibers, server rooms, and routing hardware, all very much anchored in the physical world.